On 31 October, 1991, Harry Potter and Ronald Weasley passed the First Floor Girls' Toilets when looking for Hermione Granger, so they could warn her about a troll that had been unleashed in the castle. Witnessing the troll entering the toilets, and seeing that the key was in the lock, the pair locked the room. When they heard Hermione scream from inside moments later, however, they fumbled with the key in the lock, struggling to get it open and save her.